1. Technical Field
The present invention relates to a printing device adopting an interlaced printing method, and further, a control method, a printing control device and a printing control program used for the printing device. “A printing device” in this patent description is one of printing devices which include a so-called multifunctional printer integrating therein functions of a scanner, a photocopier and so on in addition to a function of printing.
2. Field of Invention
The interlaced printing method is well known to those skilled in the art as a method which enables realization of printing of high quality. In the interlaced printing method, printing is performed on a printing medium, not at intervals of the width of a print head, but under the condition where, even when an area targeted for printing has a width equal to the width of the print head, scanning operations using the print head are performed plural times in synchronization with transporting of the printing medium performed in small steps. This method enables realization of printing at a higher resolution than a resolution at which printing is performed at intervals of a nozzle pitch of ink nozzles mounted on the print head.
In the case of performing printing by means of the interlaced printing method, printing on the whole of a printing medium by means of the interlaced printing method leads to scanning operations using the print head across a bottom edge of the printing medium (i.e., an end edge in the direction of transport of the printing medium). Therefore, even after the printing medium is pushed out from a transporting mechanism, the print head moves over the printing medium, and this operation is likely to degrade the quality of printing. In order to prevent this degradation, a method of so-called bottom edge processing, in which each printing operation is performed in synchronization with transporting of the printing medium performed by a smaller constant transport amount than a constant transport amount by which the printing medium is transported in a normal interlaced printing method, has been performed (refer to, for example, JP-A-11-268344 and JP-A-2005-81780).
However, the bottom edge processing is not always necessary for printing, and further, in order to automatically determine whether the bottom edge processing is necessary, or not, from content of data and printing conditions of a target for printing, due to an uncertainty in correspondence relations between the locations of the printing medium and the locations of the print head, it is necessary to retain raster data included in the target for printing so as to deal with the uncertainty, and further, the necessity of retaining the raster data leads to an increase in the amount of consumed memory. Thus, it is difficult to realize the automatic bottom edge processing in a printing environment where a small amount of memory is required in the printing device, such as a stand-alone printing environment.